1. Technical Field
The present invention relates to a tire puncture sealant.
2. Related Art
Automobile manufacturers are more frequently providing puncture repair kits as standard or optional equipment. Such puncture repair kits contain a tire puncture sealant as an essential constituent and can also include a compressor as an optional constituent. Actual products are generally compact packages that combine the tire puncture sealant, known as an “emergency tire puncture repairing agent” or the like, and a low capacity compressor that draws power via a cigarette lighter socket.
Conventionally, products containing a rubber latex and/or a resin emulsion, an antifreezing agent and a tackifier have been widely used as the tire puncture sealant.
Japanese Patent No. 3210863 describes “a puncture sealant for sealing a punctured tire, containing a rubber latex comprising only natural rubber latex and also containing a resin-based adhesive that is compatible with the natural rubber latex.” In addition, Japanese Patent No. 3210863 describes terpene-phenol resins and terpene-glycols as the resin-based adhesives.
Japanese Unexamined Patent Application Publication No. 2004-035867 describes “a tire puncture sealant containing at least a natural rubber latex, a tackifying resin emulsion, and an antifreezing agent, wherein a solid content (A) of the natural rubber latex is from 30 to 60 parts by weight, a solid content (B) of the tackifying resin emulsion is from 10 to 30 parts by weight and a content (C) of the antifreezing agent is from 20 to 50 parts by weight per 100 parts by weight of a total solid contents that is a sum (A+B+C) of the solid content (A) of the natural rubber latex, the solid content (B) of the tackifying resin emulsion and the content (C) of the anti-freezing agent; an aromatic modified terpene resin is used as a tackifying resin in the tackifying resin emulsion, and the tire puncture sealant can maintain high, stable sealing performance over a long period of time even when stored under harsh temperature conditions for a long period of time.”
Japanese Unexamined Patent Application Publication No. 2005-120272 describes “a tire puncture sealant having improved low temperature fluidity while exhibiting excellent puncture sealing performance, containing a natural rubber latex, a tackifying resin emulsion and an antifreezing agent comprising ethylene glycol or propylene glycol, wherein a liquid phase portion other than a solid phase portion comprising a solid content of the rubber latex and a solid content of the tackifying resin emulsion contains the glycol, water and a monohydric alcohol.”
Japanese Unexamined Patent Application Publication No. 2007-224246 describes “a tire puncture sealant that contains an antifreezing agent, a tackifier and at least one type of synthetic resin emulsion selected from the group consisting of urethane emulsions, acrylic emulsions, polyolefin-based emulsions, ethylene-vinyl acetate-based emulsions, vinyl acetate-based emulsions and poly(vinyl chloride)-based emulsions, has a hydrogen ion exponent of from 5.5 to 8.5, has similar sealing performance to conventional tire puncture sealants, has excellent storage stability at relatively low viscosities, produces scarcely any irritating odor, and corrodes steel cords very little.”
Japanese Unexamined Patent Application Publication No. 2007-224248 describes “a tire puncture sealant that contains an acrylic emulsion, an antifreezing agent, and a tackifier, has similar sealing performance to conventional tire puncture sealants, and has excellent storage stability at relatively low viscosities.”
The inventors of the present invention investigated the puncture sealant disclosed in Japanese Patent No. 3210863 by carrying out a vibration test and measuring a viscosity of this puncture sealant in order to evaluate storage performance, and learned that the viscosity had increased, thus causing sealing performance and storage performance to deteriorate.
The puncture repair kits that contain the puncture sealant as a constituent are stored inside a vehicle or inside the trunk of the vehicle in actual usage conditions and therefore move with the automobile. Therefore, the puncture repair kits are subjected to repeated vibration when the vehicle moves and are exposed to extremely high temperatures inside the vehicle or inside the trunk on hot sunny days.
By taking into account such actual storage conditions, there is a high probability that the puncture sealant described in Japanese Patent No. 3210863 will not exhibit satisfactory sealing performance after being stored in a vehicle for a long period of time.
As a result, an object of the present invention is to provide a tire puncture sealant having both excellent sealing performance and excellent storage performance.